Problem: On the way to school, Karen became fixated on the puzzle game on her phone!

<image>

The game is played as follows. In each level, you have a grid with n rows and m columns. Each cell originally contains the number 0.

One move consists of choosing one row or column, and adding 1 to all of the cells in that row or column.

To win the level, after all the moves, the number in the cell at the i-th row and j-th column should be equal to gi, j.

Karen is stuck on one level, and wants to know a way to beat this level using the minimum number of moves. Please, help her with this task!

Input

The first line of input contains two integers, n and m (1 ≤ n, m ≤ 100), the number of rows and the number of columns in the grid, respectively.

The next n lines each contain m integers. In particular, the j-th integer in the i-th of these rows contains gi, j (0 ≤ gi, j ≤ 500).

Output

If there is an error and it is actually not possible to beat the level, output a single integer -1.

Otherwise, on the first line, output a single integer k, the minimum number of moves necessary to beat the level.

The next k lines should each contain one of the following, describing the moves in the order they must be done:

  * row x, (1 ≤ x ≤ n) describing a move of the form "choose the x-th row". 
  * col x, (1 ≤ x ≤ m) describing a move of the form "choose the x-th column". 



If there are multiple optimal solutions, output any one of them.

Examples

Input

3 5
2 2 2 3 2
0 0 0 1 0
1 1 1 2 1


Output

4
row 1
row 1
col 4
row 3


Input

3 3
0 0 0
0 1 0
0 0 0


Output

-1


Input

3 3
1 1 1
1 1 1
1 1 1


Output

3
row 1
row 2
row 3

Note

In the first test case, Karen has a grid with 3 rows and 5 columns. She can perform the following 4 moves to beat the level:

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In the second test case, Karen has a grid with 3 rows and 3 columns. It is clear that it is impossible to beat the level; performing any move will create three 1s on the grid, but it is required to only have one 1 in the center.

In the third test case, Karen has a grid with 3 rows and 3 columns. She can perform the following 3 moves to beat the level:

<image>

Note that this is not the only solution; another solution, among others, is col 1, col 2, col 3.

Solution (in CPP):

Solution:
#include <bits/stdc++.h>
using namespace std;
int g[110][110];
int c[110][110];
void rowprint(int x, int t) {
  for (int i = 0; i < t; ++i) cout << "row " << x << "\n";
}
void colprint(int x, int t) {
  for (int i = 0; i < t; ++i) cout << "col " << x << "\n";
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  int n, m;
  cin >> n >> m;
  int mxr1 = 999;
  int ansk = -1;
  int minans = 134234;
  for (int i = 0; i < n; ++i)
    for (int j = 0; j < m; ++j) {
      cin >> g[i][j];
      if (i == 0) mxr1 = min(mxr1, g[i][j]);
    }
  for (int k = 0; k <= mxr1; ++k) {
    int ans = k;
    for (int i = 0; i < n; ++i)
      for (int j = 0; j < m; ++j) c[i][j] = g[i][j];
    for (int j = 0; j < m; ++j) {
      c[0][j] -= k;
      ans += c[0][j];
    }
    for (int i = 1; i < n; ++i)
      for (int j = 0; j < m; ++j) c[i][j] -= c[0][j];
    bool solved = true;
    for (int i = 1; i < n; ++i) {
      int v = c[i][0];
      if (v < 0) {
        solved = false;
        break;
      }
      ans += v;
      for (int j = 0; j < m; ++j) c[i][j] -= v;
    }
    if (!solved) continue;
    for (int i = 1; i < n; ++i)
      for (int j = 0; j < m; ++j)
        if (c[i][j]) solved = false;
    if (solved && ans < minans) {
      minans = ans;
      ansk = k;
    }
  }
  if (ansk != -1) {
    cout << minans << endl;
    for (int j = 0; j < m; ++j) g[0][j] -= ansk;
    rowprint(1, ansk);
    for (int j = 0; j < m; ++j) {
      if (g[0][j]) {
        colprint(j + 1, g[0][j]);
        for (int i = 1; i < n; ++i) g[i][j] -= g[0][j];
      }
    }
    for (int i = 1; i < n; ++i) {
      if (g[i][0]) {
        rowprint(i + 1, g[i][0]);
      }
    }
    return 0;
  }
  cout << -1 << endl;
  return 0;
}